Conditionally add stdlib APIs based on edition?

[SUPERCILEX]

Hi,
There's been some discussion on this thread where it seems like the best solution would be adding methods to a stdlib API, but only having them become active in a new rust edition. Is this possible?

[the8472]

An extension trait could be put in the prelude, which are edition-specific since #82217

[clubby789]

@rustbot label +T-libs-api